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119 results on '"Sekioka T"'

1. Trophic transfer of microplastics enhances plastic additive accumulation in fish

Author

Sekioka T, Masahiro Nakaoka, Hideshige Takada, Geok Yb, Kaoruko Mizukawa, and Toshihiro Hasegawa

Subjects
Microplastics, Myoxocephalus, Neomysis, Water column, biology, Chemistry, Environmental chemistry, Fish species, Ingestion, %22">Fish , biology.organism_classification, Trophic level
Abstract

Organisms ingest microplastics directly from environments and indirectly from food sources. Ingesting microplastics can lead to an organism accumulating plastic-derived chemicals. However, the relative contributions of the two exposure routes (direct ingestion vs. indirect ingestion) to plastic-derived chemical accumulation in an organism are unknown. Using microplastics containing different types of plastic additives, we performed exposure experiments to compare chemical accumulation patterns in fish (Myoxocephalus brandti) between the exposure from the water and prey (Neomysis spp.). We found significantly higher brominated flame retardant concentrations in fish fed microplastic-contaminated prey than fish exposed to microplastics suspended in the water. The results indicate that prey-mediated ingestion of microplastics can be a more significant route for organisms accumulating plastic-derived chemicals, suggesting that organisms at higher trophic levels are more exposed to microplastics and associated chemicals than organisms at lower trophic levels.

Published
2021
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17. Photoionization ofNe3+ions in the region of the1s→2pautoionizing resonance

Author

Oura, M., primary, Yamaoka, H., additional, Kawatsura, K., additional, Kimata, J., additional, Hayaishi, T., additional, Takahashi, T., additional, Koizumi, T., additional, Sekioka, T., additional, Terasawa, M., additional, Itoh, Y., additional, Awaya, Y., additional, Yokoya, A., additional, Agui, A., additional, Yoshigoe, A., additional, and Saitoh, Y., additional

Published
2000
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30. 4d photoionization of singly-charged Xe, Ba, and Eu ions

Author

Koizumi, T., primary, Awaya, Y., additional, Gonno, M., additional, Itoh, Y., additional, Kimura, M., additional, Kojima, T.M., additional, Kravis, S., additional, Oura, M., additional, Sano, M., additional, Sekioka, T., additional, Watanabe, Naoki, additional, Yamaoka, H., additional, and Koike, F., additional

Published
1996
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40. Genetic diversity of Carica papaya as revealed by AFLP markers.

Author

Kim, M S, Moore, P H, Zee, F, Fitch, M MM, Steiger, D L, Manshardt, R M, Paull, R E, Drew, R A, Sekioka, T, and Ming, R

Subjects
CARICA, GENETIC markers, GENETIC polymorphisms, PLANT germplasm, DNA fingerprinting
Abstract

Genetic relationships among Carica papaya cultivars, breeding lines, unimproved germplasm, and related species were established using amplified fragment length polymorphism (AFLP) markers. Seventy-one papaya accessions and related species were analyzed with nine EcoRI–MseI primer combinations. A total of 186 informative AFLP markers was generated and analyzed. Cluster analysis suggested limited genetic variation in papaya, with an average genetic similarity among 63 papaya accessions of 0.880. Genetic diversity among cultivars derived from the same or similar gene pools was smaller, such as Hawaiian Solo hermaphrodite cultivars and Australian dioecious cultivars with genetic similarity at 0.921 and 0.912, respectively. The results indicated that self-pollinated hermaphrodite cultivars were as variable as open-pollinated dioecious cultivars. Genetic diversity between C. papaya and six other Carica species was also evaluated. Carica papaya shared the least genetic similarity with these species, with an average genetic similarity of 0.432; the average genetic similarity among the six other species was 0.729. The results from AFLP markers provided detailed estimates of the genetic variation within and among papaya cultivars, and supported the notion that C. papaya diverged from the rest of Carica species early in the evolution of this genus.Key words: DNA fingerprinting, germplasm, genetic relationship, molecular phylogeny, polymorphism.Les relations génétiques au sein du Carica papaya (entre cultivars, lignées en sélection, ressources génétiques non-améliorées) et avec des espèces voisines ont été examinées à l'aide du polymorphisme de longueur des fragments amplifiés (AFLP). Soixante et onze accessions de la papaye ou d'espèces voisines ont été analysées à l'aide de neuf combinaisons d'amorces EcoRI-MseI. Au total, 186 marqueurs informatifs ont été produits et analysés. Une analyse de groupement a suggéré qu'il existe peu de variation génétique chez la papaye, l'indice moyen de similitude génétique étant de 0,880 parmi 63 accessions de la papaye. La diversité génétique entre cultivars dérivés d'un germoplasme identique ou semblable était plus faible encore. Par exemple, les cultivars hermaphrodites 'Hawaiian Solo' et les cultivars dioïques australiens présentaient des indices de similitude génétique de 0,921 et 0,912, respectivement. Les résultats indiquent que les cultivars hermaphrodites à autofécondation sont aussi variables que les cultivars dioïques à fécondation croisée. La diversité génétique entre le C. papaya et six autres espèces du genre Carica a également été évaluée. Le C. papaya était l'espèce la moins semblable aux autres, montrant un indice de similitude génétique de 0,432, tandis que l'indice moyen parmi les autres espèces était plutôt de 0,729. Les résultats obtenus avec les marqueurs AFLP permettent d'estimer avec précision la variation génétique parmi les cultivars de papaye et viennent appuyer l'hypothèse selon laquelle le C. papaya aurait divergé des autres espèces du genre Carica relativement tôt au cours de l'évolution.Mots clés : empreintes génétiques, germoplasme, relations génétiques, phylogénie moléculaire, polymorphisme.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

Published
2002
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42. The 1s–2p resonance photoionization measurement of O<SUP>+</SUP> ions in comparison with an isoelectronic species Ne<SUP>3+</SUP>

Author

Kawatsura, K, Yamaoka, H, Oura, M, Hayaishi, T, Sekioka, T, Agui, A, Yoshigoe, A, and Koike, F

Abstract

The photoion yields from O+ to O2+ were measured in the 1s–2p autoionizing resonance region of the 525–540 eV photon energy range. A multiconfiguration Dirac–Fock calculation was performed to interpret the experimental data and the results show fairly good agreement with the experimental ones. Photoionization of the N-like isoelectronic sequences of O+ and Ne3+ are discussed.

Published
2002

44. Development of Orally Active Nonpeptidic Inhibitors of Human Neutrophil Elastase

Author

Ohmoto, K., Yamamoto, T., Okuma, M., Horiuchi, T., Imanishi, H., Odagaki, Y., Kawabata, K., Sekioka, T., Hirota, Y., Matsuoka, S., Nakai, H., Toda, M., Cheronis, J. C., Spruce, L. W., Gyorkos, A., and Wieczorek, M.

Abstract

5-Amino-2-phenylpyrimidin-6-ones, some of their desamino derivatives, and miscellaneous derivatives were synthesized and biologically evaluated on both in vitro activity and oral activity in an acute hemorrhagic assay. These compounds contained an α-keto-1,3,4-oxadiazole moiety to bind covalently to the Ser-195 hydroxy group of human neutrophil elastase (HNE). Among those tested, compounds 11a−c,e,i−l(F), 11d,e,k(H), 21d,e,k(F), and 21d,e(H) showed a good oral profile. RS-Mixture 3(H) was selected for clinical evaluation based on its oral potency, duration of action, enzyme selectivity, safety profile, and ease of synthesis. Structure−activity relationships (SARs) are discussed.

Published
2001

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